I am working on a model of a .223 Caliber bullet, when I use 1 povunit =
1 inch I get a weird 'squatty' bullet.  If I scale by <1,2,1> it looks
'right' why would I not get a correctly porpotioned image without
scaling it?  the image source below will generate 2 objects, left is
using actual measurements the right is scaled.

Source code:

#version 3.1
#include "metals.inc"
global_settings
{
  assumed_gamma 1.0
}

// ----------------------------------------
camera
{
  location  <0.0, 1, -9>
  direction 1.0*z
  right     4/3*x
  look_at   <0.0, 1, 0.0>
}

light_source
{
  <-30, 30, -30>
  color red 1.0  green 1.0  blue 1.0
}

#declare A223Round =
union{
  union{
    difference {
      cylinder { .001*y, .260*y .363}
      cylinder { 0*y, .260*y .169}
    }
    lathe {
      linear_spline  10,
      <.373, 0>, <.373, .041>, <.325, .042>, <.327,.060>, <.372,.11>,
<.349, 1.436>, <.248,1.58>, <.248,1.76>, <.247, 1.76>, <.247, 1.58>
    }
    texture{T_Brass_4B}
  }
  lathe {
    linear_spline  7,
    <.222, 0>, <.222, .263>, <.223, .264>, <.17,.40>, <.06,.61>, <.02,
.6>, < 0,.5>
    texture{T_Copper_2B}
    translate <0,1.65,0>
  }
}

object {A223Round translate <-1,0,0>}
object {A223Round translate <1,0,0> scale <1,2,1>}

Post a reply to this message

Mark Palmquist wrote:
> 
> I am working on a model of a .223 Caliber bullet, when I use 1 povunit =
> 1 inch I get a weird 'squatty' bullet.  If I scale by <1,2,1> it looks
> 'right' why would I not get a correctly porpotioned image without
> scaling it?  the image source below will generate 2 objects, left is
> using actual measurements the right is scaled.


 A look at the results and then a look at the lathe objects revealed
your scaling problem. The aspect ratio you choose for width vs. height
was off a factor 2:1. I basicaly increased the numbers in the right column
by twice their value for added height and adjusted the translation of the
projectile and it came a lot closer to what it should look like. This
was all quick shot in the dark changes and you will need to correct
a couple of niggly little steps I left in the code below before it will
look good.

 Sorry about the non indented script. I Can Not read a lathe or any other type
of multi point object withouth having it in columns. It adds clarity
to my perseption.

  lathe {
  linear_spline  
  10,
  <0.373, 0.000>,
  <0.373, 0.081>,
  <0.325, 0.082>,
  <0.327, 0.120>,
  <0.372, 0.220>,
  <0.349, 2.436>,
  <0.248, 2.580>,
  <0.248, 2.760>,
  <0.247, 2.760>,
  <0.247, 2.580>}
  texture{T_Brass_4B}}

  lathe {
  linear_spline
  7,
  <0.222, 0.000>,
  <0.222, 0.463>,
  <0.223, 0.464>,
  <0.170, 0.800>,
  <0.060, 1.210>,
  <0.020, 1.200>,
  <0.000, 1.200>
  texture{T_Copper_2B}
  translate<0,2.75,0>}}

-- 
Ken Tyler

mailto://tylereng@pacbell.net

Post a reply to this message

Ken wrote in message <36D00DBC.E705B34D@pacbell.net>...

> Sorry about the non indented script. I Can Not read a lathe or any other
type
>of multi point object withouth having it in columns. It adds clarity
>to my perseption.


And indentation doesn't?! Ahh, forget it...

Margus

Post a reply to this message

Margus Ramst wrote:
> 
> Ken wrote in message <36D00DBC.E705B34D@pacbell.net>...
> 
> > Sorry about the non indented script. I Can Not read a lathe or any other
> type
> >of multi point object withouth having it in columns. It adds clarity
> >to my perseption.
> 
> And indentation doesn't?! Ahh, forget it...
> 
> Margus

Do you honestly think that Mark's format for the lathe is easier to read,
and visualize it's form, than the lathe format I provided ?

Ahh, forget it...

-- 
Ken Tyler

mailto://tylereng@pacbell.net

Post a reply to this message

Ken schrieb in Nachricht <36D00DBC.E705B34D@pacbell.net>...
> Sorry about the non indented script. I Can Not read a lathe or any other
type
>of multi point object withouth having it in columns. It adds clarity
>to my perseption.

Now you were sooo close to make it really readable:

lathe {
  linear_spline
  10,
  <0.373, 0.000>,
  <0.373, 0.081>,
  <0.325, 0.082>,
  <0.327, 0.120>,
  <0.372, 0.220>,
  <0.349, 2.436>,
  <0.248, 2.580>,
  <0.248, 2.760>,
  <0.247, 2.760>,
  <0.247, 2.580>
  texture { T_Brass_4B }
}

 lathe {
  linear_spline
  7,
  <0.222, 0.000>,
  <0.222, 0.463>,
  <0.223, 0.464>,
  <0.170, 0.800>,
  <0.060, 1.210>,
  <0.020, 1.200>,
  <0.000, 1.200>
  texture { T_Copper_2B }
  translate<0,2.75,0>
}

Indentation is only there to show you the levels of a hierarchy, like in the
left pane of the Windows Explorer, ahhh... forget it.
--
Rudy

Post a reply to this message

Alright, the lathe format looks better. But the rest of the code would still
be difficult to read without indentation (IMHO, at least).
Just as an example: my fur-generator's sampling script has
loops/conditionals nested 5 levels deep. I shudder to think what it would
look like without indentation...

Anyway, let's drop it.

Margus

Ken wrote in message <36D017FC.470AE070@pacbell.net>...
>Do you honestly think that Mark's format for the lathe is easier to read,
>and visualize it's form, than the lathe format I provided ?
>
>Ahh, forget it...
>
>--
>Ken Tyler
>
>mailto://tylereng@pacbell.net

Post a reply to this message

Ken,

 I have to agree that the lathe object definitly looks better on columns!  thanks
for the hint.  I will still indent most code but the coordinates will be in
columns.:)

My problem is I used ACTUAL measurements of a round sitting here at the computer
with a dial caliper.  why do I need to double the height values?  shouldn't the
lathe take real numbers and render a 'real' looking object?



Ken wrote:

> Mark Palmquist wrote:
> >
> > I am working on a model of a .223 Caliber bullet, when I use 1 povunit =
> > 1 inch I get a weird 'squatty' bullet.  If I scale by <1,2,1> it looks
> > 'right' why would I not get a correctly porpotioned image without
> > scaling it?  the image source below will generate 2 objects, left is
> > using actual measurements the right is scaled.
>
>  A look at the results and then a look at the lathe objects revealed
> your scaling problem. The aspect ratio you choose for width vs. height
> was off a factor 2:1. I basicaly increased the numbers in the right column
> by twice their value for added height and adjusted the translation of the
> projectile and it came a lot closer to what it should look like. This
> was all quick shot in the dark changes and you will need to correct
> a couple of niggly little steps I left in the code below before it will
> look good.
>
>  Sorry about the non indented script. I Can Not read a lathe or any other type
> of multi point object withouth having it in columns. It adds clarity
> to my perseption.
>
>   lathe {
>   linear_spline
>   10,
>   <0.373, 0.000>,
>   <0.373, 0.081>,
>   <0.325, 0.082>,
>   <0.327, 0.120>,
>   <0.372, 0.220>,
>   <0.349, 2.436>,
>   <0.248, 2.580>,
>   <0.248, 2.760>,
>   <0.247, 2.760>,
>   <0.247, 2.580>}
>   texture{T_Brass_4B}}
>
>   lathe {
>   linear_spline
>   7,
>   <0.222, 0.000>,
>   <0.222, 0.463>,
>   <0.223, 0.464>,
>   <0.170, 0.800>,
>   <0.060, 1.210>,
>   <0.020, 1.200>,
>   <0.000, 1.200>
>   texture{T_Copper_2B}
>   translate<0,2.75,0>}}
>
> --
> Ken Tyler
>
> mailto://tylereng@pacbell.net

Post a reply to this message

When I run into trouble like that, instead of fudging and running into worse
troubles later,  I would make a sphere, usually bright red or green, and see
how it looks.    In fact, in most of my scenes I have a section

#if (WantTestObjects)
sphere { <-5, -10, 0>, .5  pigment {<1,.3,.3>} finish{ambient.5 diffuse .5}}
...etc....spheres....cylinders....etc....
#endif


These test objects have high ambient values to make them show unnaturally
luminous, and have diffuse as a lighting check.  I catch a lot of weird scene
bugs by noticing funny lighting on my test objects.


My guess is your camera statement needs some adjusting.


-- 
Daren Scot Wilson
dar### [at] pipelinecom 
www.newcolor.com
----
"A ship in a harbor is safe, but that is not what ships are built for"
                                            -- William Shedd

Post a reply to this message

Mark Palmquist wrote in message <36D0AD19.445C4369@earthlink.net>...
>Ken,
>
> I have to agree that the lathe object definitly looks better on columns!
thanks
>for the hint.  I will still indent most code but the coordinates will be in
>columns.:)
>
>My problem is I used ACTUAL measurements of a round sitting here at the
computer
>with a dial caliper.  why do I need to double the height values?  shouldn't
the
>lathe take real numbers and render a 'real' looking object?
>


I think I have your problem. With Lathe you enter the radius at the point in
question. Tou are directly measuring the object's diameter. Try dividing all
of the width numbers by 2 and that should fix your problem.

Rob

Post a reply to this message

Robert G. Wright wrote:

> I think I have your problem. With Lathe you enter the radius at the point in
> question. Tou are directly measuring the object's diameter. Try dividing all
> of the width numbers by 2 and that should fix your problem.
> 
> Rob

I knew it had to be as simple as this. Good catch.

-- 
Ken Tyler

mailto://tylereng@pacbell.net

Post a reply to this message